A Bird Blog with Kate St. John

Archive for November, 2009

Since midsummer we’ve lost more than five hours of sunlight so there’s not much reason to sing. The migrant songbirds have left and only our locals (chickadees and cardinals) and some winter visitors (dark-eyed juncoes) remain. Most of them have nothing to say.

My only hope for birdsong is at dawn and the singer is the bird pictured here – the Carolina wren.

According to the range maps, Carolina wrens don’t migrate but I wonder if they change territories in the winter. What explains the new scuffles and song duels they engaged in in October? Why does each wren now sing briefly at dawn?

I hear them pipe up one after the other. “I’m here,” says the wren down the street. “I’m here,” says another across the ballpark. “I’m here,” says a third up the hill. After this brief exchange of greetings they fall silent.

After the leaves have fallen there’s one surprising bright spot in November’s forest – a yellow flowering tree nicknamed Winter-bloom.

Common Witch-hazel (Hamaelis virginiana) is a shrub or tree, 10-25 feet tall, that defies the odds and blooms from September through November. Its ragged yellow flowers aren’t noticable during October’s splash of colors but now they stand alone, odd but beautiful.

Witch-hazel has other odd traits.

Though it blooms in the fall, it doesn’t set fruit until the following August, nearly a year later.

Just before it blooms the old fruit explodes, dispersing seeds up to 20 feet away.

Witch-hazel can find water; its branches are used as divining rods. (Is that the “witch” part?)

And you probably have witch-hazel in your medicine cabinet, an extract from its bark.

Witch-hazel is a good tree for wildlife as its buds, seeds and twigs provide food for ruffed grouse, pheasants, bobwhite, deer, rabbits and beaver.

It’s good for me too because it makes me happy to see the winter bloom.

In his Sand County Almanac, Aldo Leopold called November “the month for the axe. …In winter, when we are harvesting diseased or dead trees for our fuel wood, the ring of the axe is dinner gong for the chickadee tribe… Every slab of dead bark is, to them, a treasury of eggs, larvae, and cocoons.”

Dead trees are treasure troves for woodpeckers too, and in the bird world they wield the ax. Though the leaves have fallen the weather is still warm, the larvae are still active inside the bark, and the woodpeckers can hear them.

This weekend I found a pileated woodpecker excavating a dead tree in Schenley Park. Among birds, the pileated’s beak is about as close as you can come to an ax. The bird itself is the size of a crow with a beak 1.5 to 2 inches long. That may sound small but his beak hits the wood at 13-15 miles per hour so the woodpecker experiences 10G’s of force at each blow.

It would kill you or me to slam our heads against trees but the woodpecker’s head is designed for the work. His neck absorbs the impact and his brain is cushioned by a network of flexible cartilage and spongy air-filled bone. His tongue is very long for probing the openings he creates — so long that it retracts inside to the back of his skull. It’s the right equipment for chopping trees.

Keep a lookout this month for pileated woodpeckers. November is the month for the ax.

If you enjoy these bushy-tailed creatures, have good forest habitat at your home and like to feed squirrels you’re a candidate for the “soft release” squirrel program.

The ARL Wildlife Center in Verona, PA has more than 50 orphaned squirrel pups who were rescued in September and October, very late in the breeding season. At the time, they weren’t even weaned yet and are so young they won’t be ready for release into the wild until December. By then their food supply will be buried under snow and ice. How will they survive? They need an “angel.”

Here’s how it works. As the squirrel pups grow up, they progress from bottle-fed babyhood to bouncing adolescence. When they’re ready to become acclimated to the weather they’re placed in the outdoor pre-release enclosure with a specially designed wooden box that will be their permanent home. When they’re full grown it’s time to release them, so the Wildlife Center closes the box with the squirrels inside, the box is transported to their patron’s home and mounted on a tree. Open the door and voilà! The squirrels have a new home with a safe, familiar nest. And you help them survive by putting out food for them until they no longer need it. They might leave the area but some squirrels have been known to stay and raise families in their favorite box for years to come.

The Wildlife Center is collecting a list of people who want to participate in this program. If you’re interested in being an “angel” to a couple of squirrels, call the Wildlife Center at 412-793-6900.

Tuesday afternoon I glanced out my office window and was immediately mesmerized.

A peregrine falcon was flying by, pumping hard, carrying a heavy burden. He’d killed a pigeon over Carnegie-Mellon’s campus and was taking it home to the Cathedral of Learning to eat.

Carrying prey is strenuous work. On average, a pigeon weighs 354g while a male peregrine weighs 612g (females average 976g). Imagine that your lunch weighed more than half your body weight and you had to carry it half a mile before you could eat. No way! That’s why we invented wheels.

And so I watched, unable to continue working while the peregrine slowly disappeared in the distance. My desk job is easy compared to a peregrine’s work.

I thought I’d missed my chance when I didn’t write about this plant on Halloween – more on that later – but Chuck Tague’s recent blog on tree buds gives me the perfect opportunity to discuss this scary looking plant.

Compared to the beautiful twigs Chuck photographed this one looks positively wicked. So what is it? Here are some hints.

This bud is as fat as your thumb and covered in thorns.

It grows on a tree that’s only 5 to 15 feet tall.

The trunk is very thorny too and only 1 to 4 inches in diameter.

The bud will sprout very large twice- or thrice-compound leaves that are 2 to 4 feet long!

The flower is one huge flat-topped cluster that blooms July to September.

Its fleshy, black fruit droops from the top of the tree. The berries are such good food for birds that when you find a stand of these trees in autumn you’ll find a flock of robins, too.

The name of this tree evokes Halloween.

And it is… (drum roll) … Devil’s Walking Stick (Aralia spinosa), also called Hercules-club. The trunk is so narrow it resembles a walking stick but only the Devil would dare grasp it.

Why is this bird in such a hurry to migrate south in mid-summer after raising only one brood in North America?

The answer is a surprise. It turns out that some yellow-billed cuckoos raise a second family in the thorn forests of western Mexico. And so do orchard orioles, hooded orioles, yellow-breasted chats and Cassin’s vireos.

Called “migratory double breeding” the discovery was stunning. Scientists knew of just two Old World species who did this on their journey north but no birds had been found to do it in the western hemisphere and none anywhere were known to double-breed on the southbound trip.

Gathering the evidence was truly detective work. Scientists were in the thorn forests in July and August, expecting to study the molt cycles of migratory songbirds. Instead they found males singing on territory, female birds with established brood patches and no young birds as they’d expect if the families had already bred in the forest. The clincher was when they found the nests and eggs.

If five songbird species are double-breeding in the thorn forest, why did it take so long to discover it? July and August are forbidding months in western Mexico. It’s the monsoon season with temperatures at 100 degrees, humidity at 100% and lots of biting insects. People have only recently begun to farm the region, leading to a decline in thorn forest habitat. Interestingly, the habitat decline coupled with migratory double-breeding may explain the decline of yellow-billed cuckoos in the western U.S.

So like the story of a man who has two families half a continent apart, these birds must hurry to squeeze in a second family in western Mexico, then finish their migration to tropical Central and South America. That’s what the rush is all about.

November is prime time for duck migration so despite the fact that the weather has been too nice for them I’m going to go look for ducks today.

Too good for ducks? Yes, it’s been gorgeous. Warm days, sunny skies and a south wind. Ducks are forced to migrate when the lakes freeze (no chance of that this week!) and like all fall migrants they prefer a tail wind from the north.

So I’m not expecting much but I still want to know… Are the ducks here yet?

Very soon all the trees will be bare in my neighborhood. This is already the case north of Pittsburgh.

A week ago I visited the Clarion River in Jefferson County where I noticed that even the oaks were bare. At the Allegheny Front last Sunday the leaves on the mountain had fallen but in the valley the oaks were russet, the tulip trees golden. In the valley the leaves were putting on a final show. By now it’s probably over.

However, the show isn’t over yet if you have non-native trees in your area. Trees from northern locations are out of sync with our photo period so most of them still have leaves, some are green.

Our native maples lost their leaves two weeks ago. The maples you see now with yellow and green leaves are Norway maples which respond to the amount of light they receive in Norway in October – about 10 hours per day. Pittsburgh’s days aren’t that short until early November so these foreign maples are delayed. They’re on Norway time.

Eventually even the non-natives will catch up. How will I know when all the leaves are gone? When I don’t have to rake anymore.